This invention relates to an improved squeeze film damper seal and more particularly to an improved piston ring seal and groove combination for squeeze film dampers as associated with high speed turbo machinery, for example, hot gas turbine engines such as aircraft gas turbine engines.
In a typical squeeze film shaft damper arrangement, a shaft with its associated rolling element bearing are permitted to have some limited radial motion in the supporting bearing housing. Ordinarily the annular outer race of a rolling element bearing closely fits in an annular chamber in the support housing where two opposing closely adjacent circumferential surfaces of the housing and race define a thin annular squeeze film space into which an oil under pressure is introduced for damping action on the race. The race is fitted with spaced apart concentric piston ring type seals which circumferentially engage the bearing housing to seal off the squeeze film space between the rings. One problem with dampers as described, is sealing of the fluid film squeeze film space by means of the described piston ring seals under the known variable operating conditions of the damper. For example, the noted variable operating conditions include fluid pressure fluctuations adjacent the rings which lead to sealing instability of the rings with excess damper fluid leakage and compromised damper effectiveness.